Near-infrared (NIR) imaging has been described in the literature for various clinical applications. Typically such an imaging modality utilizes a contrast agent (e.g. indocyanine green) that absorbs and/or fluoresces in the NIR. Such contrast agents may be conjugated to targeting molecules (e.g. antibodies) for disease detection. The contrast agents may be introduced into tissue intravenously or subcutaneously to image tissue structure and function (e.g. flow of blood/lymph/bile in vessels) that is not easily seen with standard visible light imaging technology.
Independently of the clinical application, endoscopic NIR imaging devices typically include multiple imaging modes as a practical feature. For example, endoscopists utilize visible spectrum color for both visualization and navigation, and an endoscopic imaging device that offers NIR imaging typically provides a concurrent color image. Such concurrent imaging devices can be realized, for example, as follows:                One conventional configuration utilizes spectral separation of the visible and the NIR light, with full color and NIR image signals acquired using separate sensors for the different color (e.g. red, green, and blue) and NIR spectral bands or a single color sensor with an integrated filter with filter elements transparent to the different spectral bands (e.g. red, green, blue and NIR). Thus, such multi-modality color and NIR imaging devices provide dedicated sensors or sensor pixels for each of the two imaging modes. Disadvantageously, this increases the number of image sensors in multi-sensor implementations or compromises image resolution when on the same sensor, specific sensor pixels are dedicated for NIR imaging while others are utilized for color imaging.        Another conventional configuration utilizes a single monochrome image sensor for sequential imaging of the visible and NIR light. The object is hereby sequentially illuminated with light in the red, green, blue and NIR spectral bands, with separate image frames being acquired for each spectral band and composite color and NIR images being generated from the acquired image frames. However, this approach, where image frames are acquired sequentially at different times, can generate objectionable motion artifacts (i.e. color fringing and “rainbow effects”) in the composite color and NIR images. These artifacts can be mitigated by increasing the acquisition or frame rate to more than, for example, 15 frames/second (fps), for example to 90 fps, or even 180 fps. Because of the high data transfer rate, high frame rates are difficult to implement for high definition images (e.g. 2 million pixels), or images having a large dynamic range (>10 bits), thus limiting image size and/or resolution.        
It would therefore be desirable to provide a system and a method for simultaneous acquisition of full-color visible light and NIR light images, which obviates the aforementioned disadvantages and does not compromise image resolution and/or introduce objectionable motion artifacts.